when , i measured impedance using CHI 660 - impedance instrument with carbon paste electrode in 5 mM [Fe(CN)6]3-/4- (1 : 1) and 0.1 M KCl solution at a potential 0.24 V , i found that the curve cut at Log freq. 4,3 and 2 i tried several time and being sure that all condition is OK but every time give the same result. please help me.
note : i did the same one before ( three months ago ) and give the good Nyquist plot
It seems your film stability affects your impedance at higher frequency. Film desorption may occur at higher frequencies and could be noticed for low binding and thin films.
I guess Artur Braun is right.
Additionally, please increase the averaging to at least 3, better 10.
Did the wiring change compared to the old measurement? There seems to be a large inductivity now. Has that been there before?
It's probably a problem with the current scale it, I had the same behavior with glassy carbon electrodes for high frequency they give this 'break'. Until I realized that other equipment that did not happen. Since these devices the current scale was not automatic.Try to change that and talk to us if the problem is over. Good luck!
Hi
I think it's may due to the inductance effect related to the external probe contact. Please check the probes.
let me know, why you applied 0.24 V as initial voltage, is it OCV ?
In CHI, we must fix the bias DC current during run as always in OFF condition.
Please check this also.
Thanks
I think, that Artur and Christian are right, you have problem with switching of the sensitivity range. Instead of automatic range setup chose manually one fixed range.
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